have to severely cut ignition timing above 6800rpm

K-Series Programmable ECU installation questions / support issues
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bfce
Posts: 5
Joined: Tue Sep 29, 2020 3:06 pm

have to severely cut ignition timing above 6800rpm

Post by bfce »

I'm having an issue where I can run 28-29 ignition timing from VTEC engagement all the way to about 6500rpm, but then have to retard all the way to 21 to avoid detonation as detected by the knock sensor. Sometimes it will still knock even at 21.
Build info:
JDM K24A (3 lobe RBB), TSX-like
PLM V2 headers, no cat, 3" straight pipe
50 degree VTC but only running around 17 near redline
RBC manifold, 72mm throttle body, cold air intake (IATs around 60F)
1000cc RC engineering fuel injectors, AEM 340 fuel pump, 55psi fuel pressure at idle (no vacuum reference so should stay there)
AFRs in the low to mid 13s
New spark plugs, properly gapped

I've wondered if my engine just has severe carbon build up, but it's still odd to me that it only happens right around 7000rpm and up. I can run 28 degrees at 6800 but must be 21-22 by 7000 to even have a chance at avoiding knock..
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